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Abstract:

A rubber sleeve for a printing press and a method for producing a rubber
sleeve is disclosed. The rubber sleeve has a rigid support sleeve and a
blanket that is wrapped around the support sleeve as well as is firmly
connected to the support sleeve. The blanket has at least a two-layer
structure with an inner layer embodied as a base layer and an outer layer
serving as a functional layer for the printing process, where the butting
edges of the blanket are connected to one another via a sealing material,
which is introduced in a gap embodied between the butting edges. The
sealing material is introduced in the gap embodied between the butting
edges while forming a channel.

Claims:

1. A rubber sleeve for a printing press, comprising a rigid support sleeve
and a blanket that is wrapped around the support sleeve and is firmly
connected to the support sleeve, wherein the blanket has at least a
two-layer structure with an inner layer embodied as a base layer and an
outer layer serving as a functional layer for a printing process, wherein
butting edges of the blanket are connected to one another via a sealing
material which is disposed in a gap defined between the butting edges,
and wherein the sealing material forms a channel.

2. The rubber sleeve according to claim 1, wherein a surface of the
sealing material disposed in the gap is set back radially inwardly with
respect to a surface of the blanket at least in sections.

3. The rubber sleeve according to claim 1, wherein a surface of the
sealing material disposed in the gap is completely set back radially
inwardly with respect to a surface of the blanket.

4. The rubber sleeve according to claim 1, wherein a surface of the
sealing material disposed in the gap is closed-cell at least in sections.

5. The rubber sleeve according to claim 1, wherein a surface of the
sealing material disposed in the gap is completely closed-cell.

6. The rubber sleeve according to claim 1, wherein the sealing material is
a compressible material.

7. A method for producing a rubber sleeve for a printing press, comprising
the steps of:making available a rigid support sleeve;making available a
flat pre-cut part of a blanket;wrapping the pre-cut part of the blanket
around the support sleeve and connecting the pre-cut part to the support
sleeve;filling of a sealing material in a liquid-like or paste-like state
in a gap defined between butting edges of the pre-cut part;forming a
channel in the liquid-like or paste-like sealing material; andhardening
the sealing material while maintaining the formed channel.

8. The method according to claim 7, wherein a surface of the sealing
material in the gap is set back radially inwardly with respect to a
surface of the blanket at least in sections.

9. The method according to claim 7, wherein a surface of the sealing
material in the gap is completely set back radially inwardly with respect
to a surface of the blanket.

10. The method according to claim 7, wherein a surface of the sealing
material in the gap is closed-cell at least in sections.

11. The method according to claim 7, wherein a surface of the sealing
material in the gap is completely closed-cell.

12. The method according to claim 7, wherein the sealing material is a
compressible material.

[0002]The invention relates to a rubber sleeve for a printing press. In
addition, the invention relates to a method for producing a rubber sleeve
for a printing press.

[0003]In principle, two methods for producing a rubber sleeve for a
printing press are known from practice.

[0004]According to a first method for producing a rubber sleeve known from
practice, such as, for example, from U.S. Pat. No. 5,316,798, a rigid
support sleeve made of metal or a composite material and which is closed
or continuous in the circumferential direction is made available, wherein
additional continuous layers of the rubber sleeve are applied
successively to this support sleeve. This is accomplished preferably in a
so-called coating method.

[0005]According to a second method for producing a rubber sleeve known
from practice, such as, for example, described in U.S. Pat. Nos.
5,351,615 and 6,484,632, a rigid support sleeve made of metal or a
composite material and which is closed or continuous in the
circumferential direction and in addition a blanket with at least a
two-layer structure as a semi-finished product are also made available,
wherein a pre-cut part of the blanket is wrapped around the rigid support
sleeve and firmly connected to the rigid support sleeve. In the process,
butting edges of the blanket must be connected to each other in order to
prevent the penetration of solutions and/or ink, wherein, for this
purpose, according to the prior art, a sealing material is introduced
flush with the surface of the blanket in an air gap embodied between the
butting edges, and wherein the blanket and the sealing material are
finished by grinding. However, the region of the sealing material
continues to represent, in terms of printing, a malfunction location or
an interruption so that continuous printing is not possible there. These
types of rubber sleeves have a limited service life because they are not
sufficiently able to absorb the stresses occurring in operation.

[0006]Starting herefrom, the present invention is based on the objective
of creating a novel rubber sleeve as well as a novel method for producing
the same.

[0007]According to the invention, the sealing material is introduced in
the air gap embodied between the butting edges while forming a channel.
The channel also forms an air gap in the process, which essentially
interrupts the outer printing layer at least partially, and as the case
may be also the inner layers.

[0008]The fact that, in the case of the inventive rubber sleeve, the
sealing material is introduced in the air gap embodied between the
butting edges of the pre-cut blanket part while forming a channel, which
allows a considerably longer service life to be realized for a rubber
sleeve because the rubber sleeve is better able to absorb the stresses
acting on the same during the printing operation. Thus, an inventively
embodied rubber sleeve is considerably less susceptible to both
mechanical destruction as well as chemical destruction than rubber
sleeves known from practice. As a result, the impact zone embodied
between the butting edges of the pre-cut blanket section is more
resistant to mechanical and chemical stresses, which ultimately results
in a significantly longer service life for the rubber sleeve. However,
also in the case of this rubber sleeve, continuous pressure that goes
beyond the area of the air gap is not possible.

[0009]Preferred developments of the invention are yielded from the
following description. Without being limited hereto, exemplary
embodiments of the invention are explained in greater detail on the basis
of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a cross-section through a rubber sleeve for a printing
press known from the prior art; and

[0011]FIG. 2 is a cross-section through an inventive rubber sleeve for a
printing press.

DETAILED DESCRIPTION OF THE DRAWINGS

[0012]The prior art will be addressed to begin with, making reference to
FIG. 1, before an inventive rubber sleeve is described in the following,
making reference to FIG. 2.

[0013]FIG. 1 shows, in section, a cross-section through a rubber sleeve 10
known from the prior art for non-continuous printing, which includes a
rigid support sleeve 11 and a pre-cut part of a blanket 12 wrapped around
the support sleeve 11 as well as firmly connected to the support sleeve
11.

[0014]The blanket 12 has at least a two-layer structure of a base layer 13
and a functional layer 14 (=printing layer), wherein the functional layer
14 is positioned radially outwardly and is used for the printing process,
and wherein the base layer 13 is positioned radially inwardly and is
connected to the support sleeve 11.

[0015]When the pre-cut part of the blanket 12 is wrapped around the
support sleeve 11, opposing butting edges 15, 16 of the blanket 12 form,
and a sealing material 18 is introduced in an air gap 17 embodied between
the butting edges 15, 16 in order to connect the butting edges 15, 16
with one another.

[0016]As a result, according to the prior art, the sealing material 18 is
introduced flush with the surface of the blanket 12 in the air gap 17,
and a surface 20 of the sealing material 18 consequently terminates flush
with a surface 21 of the blanket 12. However, the sealing material 18 is
comprised of another material than the functional layer 14 and the base
layer 13 and therefore represents, in terms of printing, a malfunction
location, over which it is not possible to print continuously and which
must be arranged in-register in the printing press, for example with
respect to the gap of any printing plates that may possibly be present.

[0017]This type of rubber sleeve 10, known from the prior art, is
preferably completely finished by grinding, i.e., both in the region of
the surface 21 of the blanket 12 as well as in the region of the surface
20 of the sealing material 18, whereby the surface 20 of the sealing
material 18 in the case of rubber sleeves known from the prior art is
embodied to be open-cell so that media such as printing ink, dampening
agent or even washing agent penetrates into the sealing material 18 and
is able to destroy the sealing material. In addition, forces in the
circumferential direction exert high mechanical stress on the adhesion
between the sealing material 18 and the blanket 12. This mechanical and
chemical stress reduces the service life of rubber sleeves known from
practice.

[0018]FIG. 2 shows, in section, a cross-section through an inventive
rubber sleeve 22 for non-continuous printing, wherein to avoid
unnecessary repetitions in connection with the inventive rubber sleeve 22
of FIG. 2, the same reference numerals will be used for the same
components as was the case in connection with the rubber sleeve 10 in
FIG. 1 known from the prior art rubber sleeve 10 and in the following
only those details of the invention that differ from the prior art will
be discussed in more detail.

[0019]As FIG. 2 shows, in the case of the inventive rubber sleeve 22, the
sealing material 18 forming a reduced air gap in the form of a channel 19
is introduced in the air gap 17 embodied between the butting edges 15, 16
of the blanket 12. A surface 20 of the sealing material 18 is
consequently set back radially inwardly with respect to a surface 21 of
the blanket 12 at least in sections, preferably completely. If need be,
in the direct connecting region of the sealing material 18 on the butting
edges 15, 16, the surface 20 of the sealing material 18 terminates flush
with the surface 21 of the blanket 12. However, at least the outer
functional layer 14 continues to remain interrupted by an air gap, in the
example in FIG. 2, and also a portion of the base layer 13.

[0020]The surface 20 of the sealing material 18 is embodied to be smooth
and closed-cell at least in sections, in particular completely. This
guarantees that no media such as printing ink and/or dampening agent
and/or washing agent is able to reach the sealing material 18 and
chemically destroy the sealing material. Due to the inventive contouring
of the sealing material 18 as a channel 19, forces acting in the
circumferential direction have no point of attack so that the mechanical
stress of the sealing material 18 in the case of the inventive rubber
sleeve 22 is considerably lower than with the rubber sleeve 10 known from
the prior art. As a whole, the service life of the inventive rubber
sleeve 22 may be increased significantly hereby.

[0021]The sealing material 18 is preferably a compressible material.

[0022]The procedure for producing the inventive rubber sleeve 22 is as
follows: first a rigid support sleeve 11 as well as a pre-cut part of a
blanket 12 are made available. The pre-cut part of the blanket 12 is
wrapped around the rigid support sleeve 11 and connected to the support
sleeve 11. A sealing material 18 in a liquid-like or paste-like state is
filled in an air gap 17 between butting edges 15, 16 of the blanket 12,
wherein a channel 19 is introduced in the still liquid-like or paste-like
sealing material 18. Following this, the sealing material 18 is hardened
while retaining the channel 19.

[0023]In the case in which a full-surface finishing by grinding of the
rubber sleeve 22 takes place, the sealing material 18 is not finished by
grinding since its surface 20 is set back relative to the surface 21 of
the blanket 12 so that its surface 20 remains smooth and closed-pore.

[0038]The foregoing disclosure has been set forth merely to illustrate the
invention and is not intended to be limiting. Since modifications of the
disclosed embodiments incorporating the spirit and substance of the
invention may occur to persons skilled in the art, the invention should
be construed to include everything within the scope of the appended
claims and equivalents thereof.